Today I'm going to give instructions on building a pocket. They are probably the most simple of 18th century garments, so this would be a good place to start or to practice hand stitching.
This would serve as the purse for most 18th century women. There are sachels or baskets, but this is still a very essential item. You can make a simple pocket out of left over linen or you can embroider the top layer. The size of extants varies widely, so you should think about what you're going to be putting in the pocket. On average, I'd say about 18"x 12". I wouldn't recommend going too large unless you're going to have hoops as well, since anything big (like a water bottle) will show through. I think my pockets are just over 12" tall, but I don't put much in them.
Once you've determined size you can rough out a pattern. Just use a straight edge and round the bottom corners and it will look fine. You're going to need three layers; one of fashion fabric and two of a sturdier linen. You'll also need some 1/2" cotton twill to bind it and 1" twill for the waist band. You can bind in a fabric as well. For fabric binding use 1" and turn the edges under 1/4" each.
After you've cut out the three layers, take the top two and cut a slit down the middle ending about half-way (not more than 9"). I'd recommend basting around those two layers before cutting so they don't shift around. Next, you'll bind the slit with the 1/2" twill leaving the ends raw. Combine all three layers, baste and bind around the outside edge. Finish the top with the 1" twill. The length should be enough to comfortably tie around your waist. Make sure to finish the ends of the tape by rolling them 1/4" twice and stitching.
If you're doing two pockets, measure out the twill the same. Tie it around your waist and determine how much space you need in the back between the two pockets.
This is a great project to take with you when re-enacting so you can practice embroidery or hand stitching. No one has to see it but you, so it's fine if it's not pretty!